<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .d1{
            box-sizing: border-box;
            background-color:antiquewhite;
            width: 50%;
            height: 850px;
            margin: auto;
            padding: 10px;
        }
        .dd1{
            float: left;
            background-color: darkgray;
            width: 100%;
            height: 30%;
            margin: auto;
            clear: both;
        }
        .dd2{
            float: left;
            background-color:cadetblue;
            width: 35%;
            height: 65%;
            margin-top: 15px;

        }
        .dd3{
            float: left;
            background-color:darkkhaki;
            width: 63%;
            height: 65%;
            margin-top: 15px;
            margin-left: 15px;
        }

    </style>
</head>
<body>
    <div class="d1">
        <div class="dd1"></div>
        <div class="dd2"></div>
        <div class="dd3"></div>
    </div>
</body>
</html>